An interesting piece by Robert Waldfogel on VoxEU attempts to estimate the quality of music over the past half decade. He uses a few different measures of quality and asks whether the advent of music sharing online increased or reduced quality. The key chart is: The spike in the 2000s is interesting, but in interpreting the measure one has to ask whether there’s anything other than quality that could be influencing it.

Essentially, he has used demand measures to proxy quality, so the most obvious bias seems to be demographics. Look for example, at the continued high demand for 60s music. That may be partly because The Beatles were great, but could it also be because that’s when the baby boomers were in their formative musical years, and so continue to demand that music from their youth? We know that there was a small echo from the baby boomers children in the ’80s and early ’90s, so could that be partially explaining the spike in demand for the 2000s music, too?

Of course, the demographic argument works both ways: maybe the large number of young people in the sixties and noughties also increased the supply of music, too. That may lead to a corresponding increase in the quantity of high-quality music, which would lead to it being disproportionately weighted in the index.

If anyone’s an expert in this field then let us know why you think Waldfogel’s results hold, or not. Alternatively, unfounded speculation is welcome.